Heat, dry weather pose problems for landscape plants
By Devon Johnson
High temperatures, combined with dry weather, pose a threat to Virginia’s home landscapes. Vegetable gardens, lawns, and even trees and shrubs are all susceptible to the effects of drought, including desiccation and increased vulnerability to pest and disease problems.
Virginia Cooperative Extension agents and Extension Master Gardeners are positioned across the commonwealth to offer guidance for gardeners dealing with dry conditions. For many home gardeners inspired to plant vegetables in response to COVID-19 lockdown restrictions, dry weather presents a special challenge.
“Dealing with dry conditions can be especially hard for vegetable gardeners as many plants need consistent water to continue to produce and some need rain at critical times, such as corn during silking,” said Amy Byington, Lee County, Virginia, Cooperative Extension. “In Lee County, our gardeners are struggling to keep their plants healthy and watered. Any time plants become stressed, disease and other issues are more likely to present themselves.”
Trees and shrubs are also susceptible to drought, though how they respond depends on a few factors, including species, the time elapsed since transplanting, and soil type, according to Alex Niemiera, a professor in the School of Plant and Environmental Sciences.
“Some plant species are very tolerant of drought, some very intolerant, some in-between,” Niemiera said. “Recently transplanted plants will be more vulnerable to drought stress compared to plants that have been planted for about a year or more. It is important to water recently planted plants regularly. Lastly, soil type will affect drought response. Plants growing in moisture-retentive soils will fare much better than those growing in less retentive soils.”
For help evaluating the type of soil you have and the susceptibility of your trees and shrubs to drought, contact your local Extension Master Gardeners via your Virginia Cooperative Extension office.
“The very hot and mostly dry summer in Virginia is presenting some real challenges to Virginia gardeners,” said Frank Reilly, Central Rappahannock Extension Master Gardener. “There are the usual problems with heat and dry, such as plants wilting, trees prematurely dropping leaves, and fewer flowers than we expect from our favorite flowering plants. Some folks are also reporting that their tomatoes and even some peppers have stopped setting fruit.”
Watering deeply can help stave off the effects of temperature and drought.
“If gardeners can irrigate or water their gardens, they need to be mindful of a few things,” Byington said. “It is better to water a lot at one time, rather than to just give small amounts of water more often. Watering thoroughly allows plants to develop the deep roots they need to obtain moisture and nutrients from deeper in the soil.”
Gardeners should also be mindful to water in the morning or the evening, but not during the hottest parts of the day, Byington added.
“Water early in the morning to allow plants to get moisture before dealing with the hot day or water late in the evening to allow plants to replenish after the day,” she said. “Watering when temperatures are cool, allowing for less evaporation, works as well.”
As climate change makes weather patterns more unpredictable and makes exceptionally dry periods more common, home gardeners will have to adapt to new challenges in the landscape.
“Because of climate change, some plants will have difficulty in the new warmer temperatures from things like water stress, but also due to increased pressure from pests, or from pests that are new to their yard,” Reilly said. “As climate change makes weather more unpredictable, it’s going to be more important for homeowners to plan landscapes/choose plants accordingly, and pay attention to pest announcements. That’s why Virginia Cooperative Extension and Extension Master Gardener volunteers are more important than ever.”
For more help planning a landscape more tolerant of hot, dry weather, troubleshooting irrigation in the home vegetable garden, or tending to drought-stricken trees and shrubs, contact your local Virginia Cooperative Extension office and your local Extension Master Gardener program.